There are numerous examples of collapsible boxes, bins, dumpsters, storage containers and the like available. These structures are commonly made form materials such as cardboard, wood, and metal. Plastic structures are also known and typically comprise injection molded plastic components.
Collapsible containers often have wall components which are pivotally attached to a base or pallet member along a horizontal hinge axis (see for example U.S. Pat. Nos. 3,874,546; 4,062,467; 4,674,647; 4,775,068; 5,419,448; 6,015,056; 6,098,827; 6,863,180; 7,017,766; 7,044,319; 7,059,489; 7,156,249; and CA Pat. No. 1,065,777). The wall components themselves may comprise pivotally attached sections, most typically along a horizontal axis (see for example U.S. Pat. Nos. 3,796,342; 5,038,953; 5,253,763; 6,726,046; 6,913,161; 7,137,522; 7,175,040 and CA Pat No. 1,333,055). By contrast, collapsible containers having a wall component that comprises sections which are pivotally connected along a vertical axis are less common (see for example U.S. Pat. Nos. 3,865,269; 4,630,746; 5,361,923; 6,182,849; 6,229,011). Collapsible containers often have an open top but may also have removable or attached lid components (for examples of containers having a pivotally attached lid see U.S. Pat. No. 4,624,381 and US Pat App. No. 2009/0134057A1).
To impart rigidity and strength to plastic components used in containers, the components are often ribbed or open framework structures, in which flanged sections may be arranged perpendicularly to the vertical or load bearing axis (see U.S. Pat. Nos. 3,985,258; 5,474,197 and 6,484,898).
In contrast, commonly owned US Pat. App. No. US2007000827311, describes the use of twinned wall plastic components to impart high structural strength and rigidity to a collapsible storage container, while at the same time minimizing container weight. The container has an integral roof and end walls which fold inwardly along a horizontal axis and serves as a collapsible storage system. Also present are elongate concave indentations which increase the flexural rigidity of the wall components.
U.S. Pat. No. 6,631,821, describes an open topped knock down bin, which comprises twinned wall (or “double wall”) components. The double wall components consist of a base, two ends walls and two side walls and are preferably composed of rotomolded plastic. Although the knock down bin can be disassembled, none of the walls are pivotally attached to the base in such as way as to facilitate rapid collapsing of the bin. Instead, the bin has a network of horizontally and vertically penetrating reinforcing bars to hold the bin corners together and which must be removed prior to deconstructing the bin. Also, the bin does not contain wall components which can be folded back on themselves so as to facilitate storage within the periphery of the base when in a collapsed state. Finally, the bin has vented walls and is not weather proof.
U.S. Pat. No. 4,693,386 and CA Pat. No 1,159,379 each describe a collapsible shipping container made out of twinned wall rotomolded plastic components. In each case, the containers have four side walls, a base and an open top. All side walls are pivotally attached to the base. Neither container includes a wall component having a vertical axis along which two or more wall sections are pivotally joined.
It would be desirable to have an open-topped, collapsible container comprising twinned wall plastic components which are strong and light weight and where the components can be easily and securely stored within the container, when the container is in a collapsed state. Such a container would be particularly useful if it allowed both side and top access while in an erect position.